126378-50-5Relevant academic research and scientific papers
4. Chelate-controlled asymmetric synthesis of 2-substituted 2,3-dihydropyridin-4(1H)-ones: Synthesis of D- and L-aminodeoxyaltrose derivatives
Streith,Boiron,Paillaud,Rodriguez-Perez,Strehler,Tschamber,Zehnder
, p. 61 - 72 (2007/10/02)
Asymmetric methylation and phenylation of the chiral pyridinium salt 7, as well as methylation of chiral pyridinium salt 18, with Grignard reagents occurred in good yield and with good-to-excellent diastereoselectivities. These results are best explained by assuming chelate control to govern the asymmetric alkylation/arylation process. The minimum-energy conformations of the out-of-plane twisted pyridinium salts 7 and 18, as determined hy the 'Molecular Simulations Cerius-Dreiding II' program, are in good agreement with the postulated asymmetric chelate-control mechanism.
Asymmetric synthesis of 2-alkyl(aryl)-2,3-dihydro-4-pyridones by addition of Grignard reagents to chiral 1-acyl-4-methoxypyridinium salts
Comins, Daniel L.,Joseph, Sajan P.,Goehring, R. Richard
, p. 4719 - 4728 (2007/10/02)
The asymmetric synthesis of 2-alkyl(aryl)-2,3-dihydro-4-pyridones 3 by addition of various Grignard reagents to chiral 1-acyl-4-methoxypyridinium salts was studied in detail. Chiral pyridinium salts formed from 4-methoxy-3-(triisopropylsilyl)pyridine (2f), and (-)-8-arylmenthyl chloroformates, or (-)-trans-2-(α-cumyl)cyclohexyl chloroformate, gave the best results, with diastereomeric selectivities ranging from 60 to 94%. When 4-methoxy-3-(trialkylstannyl)pyridines were used, destannylated 2-alkyl-2,3-dihydropyridones 3a resulted in good yield. The size of the C-3 substituent, the auxiliary, the solvent, the reaction temperature, and the structure of the Grignard reagent were varied to determine their effect on the yield and the degree of asymmetric induction. The chiral auxiliary and the C-3 triisopropylsilyl group can be removed from 3f, and the auxiliary recovered, on treatment with sodium methoxide in methanol followed by aqueous acid. The resulting 2,3-dihydropyridones 8 are useful chiral building blocks for the enantioselective synthesis of various alkaloids.
Asymmetric Synthesis of 2-Alkyl(Aryl)-2,3-dihydro-4-pyridones by Addition of Grignard Reagents to Chiral 1-Acyl-4-methoxypyridinium Salts
Comins, Daniel L.,Goehring, R. Richard,Joseph, Sajan P.,O'Connor, Sean
, p. 2574 - 2576 (2007/10/02)
Grignard addition to a chiral 1-acyl-4-methoxypyridinium salt provides synthetically useful 2-alkyl(aryl)-2,3-dihydro-4-pyridones in high diastereomeric excess.
